1

Preheat the oven to 200°C, fan 180°C, gas mark 6. Put the celeriac on a baking tray and roast for 35-40 minutes, until tender and golden.

2

Meanwhile, put 500ml milk in a large pan with the fish, onion, cloves and bay leaf. Bring to a simmer and poach for 4-5 minutes until the fish is just cooked. Use a slotted spoon to lift the fish from the milk and set aside. Remove the onion, cloves and bay leaf from the milk and discard, saving the poaching liquid.

3

Heat a splash of water in a wide pan, add the spinach and cook for 1-2 minutes until wilted. Remove from the pan, squeeze out any excess moisture and roughly chop.

4

Melt 50g of the low-fat spread in a large pan, then add the flour. Stir to make a paste, then cook for 2 minutes. Gradually add the poaching liquid, stirring to combine. Bring to a simmer and cook for 2 minutes, until the sauce thickens. Flake the cooked fish into large pieces and stir into the sauce, along with the cooked spinach and the dill. Season to taste.

5

Mash the roasted celeriac with the remaining low-fat spread and the 2 extra tablespoons milk, then season to taste.

6

Put the fish mixture into a baking dish and top with the mash. Bake for 20 minutes, until golden and bubbling.